Elevating platform for typewriters



Jan. 6, 1953 F. w. BOLLHOEFER 2,624,535

ELEVATING PLATFORM FOR TYPEWRITERS Filed Aug. 20, 1947 2 SHEETS-SHEET 1 M Ji TPANZ 74 EJLLHJEPEH AT TUHNEY Jan. 6, 1953 F. w. BOLLHOEFER 2,624,535

EDEVATING PLATFORM FOR TYPEWRITERS Filed Aug. 20, 1947 2 SHEETSSHEET 2 7 k 35 INVEA TOR. Eg F 5 E 7% HA/VZ ELL/{05F H A ATTUHNE) Patented Jan. 6, 1953 UNITED OFFICE 2 Claims.

The invention relates to improvements in elevating carriages and more particularly to a novelly constructed typewriter mounting of a kind thatcan be raised into a position for convenient use or lowered so :as to be concealed in a drawer or beneath the topof a desk quickly and easily.

It is customary to provide a desk with 2. normally concealed shelf or a drawer adapted to have a typewriter mounted thereon so as to be moved from a concealed position within the desk into anexposed position for use. Most desk con structions, however, are such as to limit the height at which the typewriter is supported when positioned for use and as a consequence the typewriter frequently is'below the plane most desired for convenient operation and efficient use. Various known devices or mechanisms heretofore devised to enable the typewriter to be raised above the plane of its mounting support are very unsatisfactory from the standpoint of ease of manipulation, steadiness of the supporting structure, and selection of the elevation most suited to the needs of the operator.

It is therefore an object of the invention to provide a vertically adjustable mounting of the kind which may be adjusted quickly and easily to any desired elevation within the range of its adjustability.

Another object is to provide a durable, inexpensively constructed adjustable mounting for a typewriter, and one which embodies many novel features of construction.

Another object is to provide a vertically adjustable mounting which is constructed in a manner to afford the rigidity required to provide a firm wobble-proof support for a typewriter.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings. Other embodiments of the invention embodying the same principle may be used, and structural changes may be made as desired by those skilled in the art without de-, parting from the present invention and the purview of the appended claims.

In the drawings:

Fig. 1 is a side elevational view of the elevating carriage showing it mounted upon a support.

Fig. 2 is a horizontal sectional view taken substantially on line 22 of Fig. 1.

Fig. 3 is a front elevation view showing portions of the dust guards broken away.

Fig. 4 is a fragmentary rear end elevation view of the base illustrating the operable connection between the actuating element and the adjusting means.

Fig. 5 is a sectional detail view taken on line 5-5 of Fi 4.

The elevating carriage embodying the features of the present invention includes a base i I and a platform 12 superposed above said base. The base is substantially rectangular and includes suitable end flanges i3 and side flanges H] which extend upwardly therefrom around the periphery thereof. The platform 12 is rectangular also and it has depending end flanges l5 and side flanges it and includes a suitable cushion ll preferably in the form of a rubber mat secured firmly to the top face thereof to afford a resilient surface upon w ich a. typewriter lil is mounted.

The platform i2 is adapted to be moved vertically relative to the case M so that the elevation of the typewriter may be varied to suit the needs of the operator. To this end toggle-link structures, generally indicated at 15, provide adjustable means connecting the platform [2 to the base H. The toggle-link structures It preferably are located one at each corner of the superposed base and platform in the manner shown and each includes a pair of links 2d and 21. Inasmuch as the construction of each of the toggle-link structures is identical, the following description will concern itself with the construction of one of said structures and like numerals will identify corresponding parts of each.

The link has one of its ends pivotally secured, as by a rivet 22, to the side wall l of the base ll adjacent an end flange IS. The other link 2i is pivotally secured as by a rivet 23 to the depending side flange is of the platform l2 adjacent an end flange iii. The link 26 is pivotally secured intermediate its ends to the link 2| substantially midway between the ends of said lastnamed link as by means of a tie-rod 24. The tie-rod extends transversely of the elevating carriage and has its ends connected one to each of the link structures located at the same end of the assembly. In this manner, the link structures are connected in pairs. The tie-rod 2d aifords stability to prevent transverse shifting of the platform !2 relative to the base I l. The free end of the link 2! extends downwardly towards the base ii and carries on its free end a roller 25 adapted to roll along the top face of the base II when the link is moved into various positions of adjustment and the free ends of the links 2!] travel along the bottom surface of the platform I? to help support the load thereon.

The roller 25 is mounted closely adjacent to the inside face of the link 2! on an axle 26 which extends transversely across the elevating carriage to further reinforce the link structures against transverse shifting. It should be quite evident at this time that any movement of the pivotally connected links 23 and 2! relative to each other will raise or lower the platform l2 relative to the base ll. Such movement of the links is attained through operation of manually actuable means including screw-threaded rods operatively associated with the axle 26 of each pair of link structures.

As best shown in Fig. 2, the base II has a pair of screw-threaded rods 21 extending longitudinally thereof and journaled at their ends in the end flanges I2. The rods 27 are located one closely adjacent to each of the side flanges I 4 and each includes right and left-handed screwthreaded portions 28 which extend through tapped openings 29 in the axles 26. Obviously, any rotation imparted to the screw-threaded rods 21 will move the axles 26 longitudinally of the base II to thereby adjust the relative positions of the links for raising and lowering the platform I2.

Means is provided for rotating the screwthreaded rods 27 in either direction and to this end an operating shaft 32 is provided in the base II midway between the screw-threaded rods 21. This operating rod is journaled in the end base flanges I3 and one end thereof projects forwardly of one of the end flanges to receive firmly thereon an operating crank 3I. The other end of the shaft 39 extends rearwardly of the other end flange I2 and it carries on its projecting end a disc 32 which is firmly secured thereon, as by set screw 33, for rotation therewith. Similar discs 34 are firmly secured to projecting ends of each of the screw-threaded rods 21. Upon referring to Figs. 4 and it will be observed that each disc 32 and 34 has a pintle pin 35 eccentrically arranged thereon and extending rearwardly thereof. A tiebar 36, of sufficient length to bridge the spaces between the discs 32 and 34, is pivotally mounted on each of the pins 35 to thereby provide a bellcrank connection between the manually rotatable disc 32 and the discs 34. The pins 35 also carry links 31 which extend upwardly diagonally therefrom as shown and have pivotally connected to their free ends a second tie-bar 38.

In operation, the crank 3I is manipulated to rotate the shaft 39, which rotation is transmitted through the discs 32, 34 and tie-bars 36 and 38 to the screw-threaded rods 21. The construction and assembly is such that utmost rigidity is imparted to the link structures through their connection with the screw-threaded rods, which in turn are prevented from back-lashing or rotating inadvertently through the tie-bar connections operatively associating it with the manually rotatable shaft 30.

If desired, a dust guard may be provided on the front end of the elevating carriage. As shown, this guard consists of a pair of dust guard plates 39 and M, suitably mounted as by screws 42 and 43 respectively, on the related end flanges of the base II or platform I2. These dust guard plates are of such length as to overlap, thereby completely closing the front of the elevating carriage irrespective of the position of elevation assumed by the platform I2. Suitable recesses 44 may be provided in the dust guard plate M to enable it to move downwardly beyond the plane of the journals for the shaft 30 and screw-threaded rods 21.

The dust guard plate 39 also preferably de pends below the bottom plane of the base II and is provided on its lower edge with an inwardly turned flange 45 coextensive with its length to be engaged beneath the support 46, which in this instance may be a shelf or platform of the desk in which the elevating carriage and typewriter normally are concealed.

Although a preferred embodiment of the invention has been disclosed in the accompanying drawings and described in detail in the foregoing specification, it should be understood that the invention is capable of adopting a wide variety of modifications without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. An adjustable carriage comprising 8, rectangular base adapted to be placed upon a support, a rectangular platform superposed over said base, two pairs of X-shaped link structures each having upper and lower extensions, the link structures each connecting a corner of the platform to a related corner of the base, a pair of screwthreaded rods journalled in said base, the links of each pair having one of their lower extensions threaded on one of said rods, one upper extension of each link structure being connected to said platform with the other of said upper extensions being free to slide along said platform, and single means operable to rotate the screw-threaded rods in unison to move the extensions and thereby adjust the relative positions of the links to carry the platform toward and away from the base.

2. An adjustable carriage comprising a rectangular base adapted to be placed upon a support, a rectangular platform superposed over said base, two pairs of X-shaped link structures having upper and lower extensions, the link structures each connecting a corner of the platform to a related corner of the base, a pair of screwthreaded rods journalled in said base, the links of each pair having One of their lower extensions threaded on one of said rods, one upper extension of each link structure being connected to said platform with the other of said upper extensions being free to slide along said platform, a rotatable actuable element on said base, and an eccentric link structure connecting said actuable element with each screw-threaded rod so as to impart uniform rotation to the rods upon actuation of the actuable element to adjust the link structures for raising and lowering the platform.

FRANZ W. BOLLHOEFER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,708,903 Schroder Apr. 9, 1929 1,799,261 Stoody Apr. 7, 19 1 2,415,820 Herring Feb. 18, 1947 2,531,880 Herring Nov. 28, 1950 

